Pressurized proportional mixing device



May 3, 1960 R. E. PERLEWITZ 2,935,057

' PRESSURIZED PROPORTIONAL MIXING DEVICE Filed June 4, 1958 2Sheets-Sheet l I Z I IN VEN TOR.

EOJEET' E. PEEAEWITZ Q Arrae/vsys y 1960 R. E. PERLEWITZ 2,935,057

PRESSURIZED PROPORTIONAL MIXING DEVICE Filed June 4, 1958 2 Sheets-Sheet2 INVENTOR. fizz-er E. 1%ELEW/7'Z BY M M 7 A TTOE/VE Y1 PRESSURIZEDPRUPORTIONAL MEXING DEVICE Robert E. Periewitz, Thiensville, Wis.,assignor to Tecumseh Products Company, Tecumseh, Mich, a corporation ofMichigan Application June 4, 1958, Serial No. 739,729

12 Claims. (Cl. l2373) This invention relates generally to devices formixing fuel and lubricant, such as gasoline and oil, in predeterminedproportions and then supplying the mixture to an internal combustionengine. More particularly, the invention relates to such a device whichuses crankcase pressure of the engine to feed the fuel and lubricant.

It is generally an object of the present invention to provide animproved pressurized proportional mixing device of the above type. Morespecifically, the invention contemplates an automatic mixing device ofthis character in which the sizes of the conduits for the fluids to bemixed are in a ratio determined by the ratio of the fluids desired inthe mixture. Furthermore, theinvention provides a device of the abovetype which has means for preventing excessive pressure from flooding thecarburetor, this excessive pressure being the result of exhaust portplugging or throttle position.

Another more specific object of the present invention is to provide apressurized proportional mixing device of the above type which providesa faster build-up of pressure in the oil supply chamber than in thegasoline supply chamber, when the engine is first started. This 1Another object of. the invention is to provide a pressurizedproportional fuel and lubricant mixing device for an internal combustionengine which insures unifor'mity of'the mixture and which requires lessoil than conventional systems. Byrequiring 'less oil for completelubrication, there is less tendency of the engine tosmoke, less sparkplug fouling and the parts of the engine remain cleaner.

A further object of this invention is to provide an improved combinationrelief valve and fill cap assembly for a pressurized liquid storagetank; The mixing device provided by this invention permits the fuel andlubricant supply to be located below the level of the carburetor whichresults in a system that is fiexibleas to installation.

Thes e and other object and advantages of the present invention willappear hereinafter as this disclosure progresses, reference being had tothe accompanying drawings, in which; g

1 Figure 1 is a perspective view of a two-stroke internal combustionengine utilizing the present invention;

Figure 2 is an exploded fragmentary view of the pressure inlet chamberand the mixing device shown in Figure 1 but on an enlarged scale, someof the parts being in section or broken away for clarity;

Figure 3 is a sectional view of the pressure regulator 1 shown in Figure1 but on an enlarged scale, certain parts 2 being in section, brokenaway or removed for clarity in the drawings;

Figure 4 is a vertical sectional view through the mixing chamber andtaken generally on line 4-4 of Figure 2, but on an enlarged scale;

Figure 5 is a view similar to Figure 1 but showing a modified form ofthe invention;

Figure 6 is an enlarged and exploded, perspective schematic view of thecheck valve assembly shown in Figure 5; and

Figure 7 is a vertical sectional view of the supply and mixing device asshown in Figure 5, but on an enlarged scale.

Referring in greater detail to Figures 1 to 4 of the drawings, atwo-stroke cycle internal combustion engine 6 has been shown more orless schematically and includes a carburetor 7 through which a mixtureof fuel and lubricant, such as gasoline and oil, respectively, is passedinto the combustion chamber thereof in the well-known manner. The enginealso includes a-crankcase 8 which is pressurized during operation byreciprocation of the pistons (not shown) as is conventional practice.

A pressure conduit 10 extends from the crankcase chamber and into apressure regulator 12. The pressure regulator has a flexible diaphragm14 held between complementary housings 15 and 16 and defining a chamber17 with the latter. An arm 18 is pivotally mounted on pin 19 within thehousing 16 and carries a valve stem 20 which is urged to its closedposition against valve seat 21 by the action of spring 22. The otherside of the diaphragm is open to the atmosphere via port 23 and a spring24 acts on the diaphragm to urge the block 25 associated therewithagainst the arm 18 and the influence of spring 22.

Conduit 26 places regulator chamber 17 in communication with thepressure intake passage 28 of the pressurized mixing device 30.

The mixing device 30 is shown for illustration purposes as being acontainer 32 which is separated from the engine 6. However, the device30 may be connected directly to the engine and made an integral partthereof.

The container 32 is divided into two pressurizable compartments orchambers 33, 34 by the dividing wall 35, for storing a supply offuel'and lubricant, respectively. The container has a cover 36 which inturn has removable caps 37, 38 for filling the chambers 33, 34,respectively, with a fuel such as gasoline and a lubricant such as oil.A vent 40 is provided in the fuel cap 37 for purposes that will laterappear.

The cover 36 includes an enlarged portion 41 which may be considered asan integral part thereof and this portion in turn has a removable top42.

Pressure-from the engine crankcase is introduced from passage 28 intothe fuel chamber 33 via the pressure port 43. Pressure is introducedinto the lubricant chamber 34 from passage 28 through the port 44. Thediameter of the port 43 is considerably less than that of port 44. Byrestricting the fuel pressure port more than the lubricant pressureport, pressure is built up faster in the lubricant supply chamber 34than in the fuel supply chamher, when the engine is first started. Thisarrangement insures that fuel does not enter the engine before thelubricant and causing the engine-to run without lubrication whenstarting.

The sizes of ports 43 and 44 may vary depending for I one thing, on theviscosity of the lubricant. Practice has indicated good results with afuel pressure port about 2% times smaller than the lubricant port, whenusing an oil lubricant of SAE #30 viscosity, for example, an orifice ofabout inch diameter for the lubricant tank pressure line and about 36inch diameter for the fuel tank pressure line.

2,935,057 V i A A mixing chamber 48 is placed in communication with thefuel chamber 33 by means of tube 49, and with the lubricant chamber 34by means of the smaller tube 50. These tubes extend downwardly intotheir respective chambers and terminate adjacent the bottom thereof. Asshown best in Figure 4, the upper ends of tubes 49 and 50 extendupwardly to a point adjacent the top of chamber 48 and above the levelof the mixture therein. By having these tubes extend into the air pocketabove the level of the mixture, one fluid is prevented from entering thesupply chamber for the other fluid. Furthermore, the supply of one fluidis exhausted before the other, pumping of the remaining fluid willcease, as will appear later.

The ratio of the cross sectional areas of tubes 49 and 50 is determinedby the ratio of fuel and lubricant desired thereby providing properfuel-lubricant ratio at all times regardless of the rate of mixture feedto the enlue. For example, with the device as shown, for a fuel tolubricant ratio of 16 to 1, a tube cross-sectional area ratio of 83 to 1has been found satisfactory.

Pressure in chambers 33 and 34 forces fuel and lubricant up theirrespective tubes 4-9and 50 and into the mixing chamber where they arethoroughly mixed and discharged via conduit 52. to the carburetor 7.

Conduit 52 preferably has a small internal diameter than either of thetubes 4-9 and '50. As a result, if dirt should enter the supplychambers, it would be more likely to plug this mixture supply line 52,rather than either of the fuel or lubricant tubes 49 and 50. Therefore,the engine would stop rather than having continued pumping of only onefluid or the other.

The pressure regulator 12 serves to'hold the pressure in the chambers 33and 34 substantially constant and prevents excessive pressure fromflooding the carburetor. This excessive pressure may be caused, forexample, by the throttle setting of the engine or exhaust port plugging.

The vent hole40 is provided in the gasoline cap in order to prevent oilfrom collecting in the pressure line 2-6 and thereby causing pressurevariations. Stated otherwise, the vent 40 results in continuous flowthrough the pressure line 26 into the gasoline chamber and keeps thepressure line 26 free of liquid. It also results in slightly lesspressure in the gasoline chamber than in the oil chamber, which has theeffect of offsetting the difference in density between the oil andgasoline.

The modification of the invention as shown in Figures to 7 functions ina manner similar to the Figure 1 device but provides different pressurecontrol means. In this modification, the pressure regulator 12 as shownin Figure 1 has been eliminated and a relief valve device 60 (Figure 7)provided in the gas cap 61. In addition, a check valve assembly 62 hasbeen mounted on the crankcase and pressure is furnished therethrough tothe conduit 26 which communicates with the mixing chamber as mentioned.

Elements which are similar. or common to both the Figure ,1 and Figure 5devices have similar reference numerals.

Referring in greater detail to Figures 5 and 6, the check valve assembly62 comprises a cast body 64 having apertures 65 which receive cap bolts66 that are threaded into the engine and hold the mounting face 67 ofthe assembly in sealing engagement with the engine. The chamber 68 ofthe assembly communicates with the engine crankcase and crankcasepressure is introduced through the L-shaped passageway 69 into bore 70.A check valve 71 is provided in the body and across the bore 70 and isshown for illustrative purposes as being of the. reed valve type.Conduit 26 is in communication with the valve which acts as a one-waycheck for the crankcase pressure. The particular L-shaped passageway andbore as shown minimizes the amount of oil and gasoline passing out ofthe crankcase with the air.

Pressure from the crankcase is conducted via conduit 26 to the pressureinlet chamber 28 (Figural) which conducts it to the oil and gas tanks,respectively, through tubes 44 and 43, previously described.

As shown in Figure 7, an auxiliary gas chamber 73 is provided above themain gas chamber 33 and is defined by the bafiie-like housing 74 securedto the cover 36. The housing has a port 75 connecting chambers 73 and 33and pressure enters via tube 43 into chamber 73, through port 75, intochamber 33 and thereby forces fuel out the tube 49, previouslydescribed, and into the mixing chamber 48.

The housing 74 and the separate chamber 73, into which the pressure isintroduced before entering the main gas chamber 33, prevents fuel fromblowing out the relief valve assembly 68 in the gas cap 61.

crankcase pressure forces lubricant from chamber 34 into the mixingchamber 48 in the same manner as in the device of Figure 1.

The construction of the relief valve assembly 60 is such as to preventfuel from escaping therethrough and thereby creating a fire hazard andthe outside of the gas cap remains dry. This valve functions to relievepressure over a predetermined amount from the gas chamber and also fromthe oil chamber 34 which is in communication with the gas chamber viathe pressure inlet chamber 28.

Furthermore, this valve performs the function of the vent 40in theFigure 1 device, namely, preventing oil from collecting in the pressureline 26. This is accomplished by the fact that the relief valve 60 isset to open at a pressure less than that of the crankcase. As a result,a continuous flow of air through pressure line 26 keeps the latter freeof liquid. a

A gas cap 61 is threadably engaged in the cover 36 and contains a bore77 and counterbores 78 and 79. A disc 80 is located in bore 79 and has aseries of apertures 81 extending therethrough. A piece of filteringmaterial 82, such as chamois, is located on the underside of the disc80, and the disc and filter are held captive in the bore 79 by thecup-like member 83 having an axial flange 84 press-fitted into the bore79. A series of apertures 85 extend through flange 84 and it will benoted that apertures 81 and 84 are positioned at right angles to oneanother.

A stem 86 is secured at its lower end in the disc 80 and extendsupwardly through the bores 77 and 78, and terminates in an enlarged cap87. A disc 88 is loosely mounted around the stern and is resilientlyurged against the disc 80 to seal the apertures 81. The means foryieldingly holding the disc 88 in sealing position takes the form of aspring 89 which bears against the disc and the stem cap 87.

The chamois located between the angularly disposed apertures 81 and 84prevents the fuel from escaping through the relief valve and have provento be particularly effective in keeping the escaping air dry and free offuel vapor.

With the present invention, fuel and liquid are auto! matically mixed inpredetermined proportions. When the engine is started, the immediateflow of lubricant into the combustion chamber of the engine is assuredbecause of the more rapid build-up of pressure in the lubricant chamberthan in the fuel chamber.

In addition, and importantly, if the engine runs out of fuel, the enginewill stop pumping lubricant because of the pressure being balanced inthe mixing chamber and the lubricant chamber. If the engine runs out oflubricant, it will also stop pumping fuel because of the equalizedpressures in the mixing chamber and the fuel chamber. Under thesecircumstances also the engine will stop and it cannot be run tight fromthe lack of lubricant.

Various modes of carrying out the invention are contemplated as beingwithin the scope of, the following claims particularly pointing out anddistinctly claiming the subject matter which is regarded astheinvention.

1. In combination with an internal combustion engine having apressurized crankcase and also having a carburetor through which a fueland lubricant mixture is passed to said engine, a fuel and lubricantmixing device comprising, separate fuel and lubricant supply chambersadapted to be pressurized by pressure from said crankcase, a mixingchamber, fluid conducting means for each of said fuel and lubricantchambers for placing them in communication with said mixing chamber, andconduit means placing said mixing chamber in communication with saidcarburetor.

2. In combination with a two-stroke internal combustion engine having apressurized crankcase and also having a carburetor through which a fueland lubricant mixture is passed to said engine, a fuel and lubricantmixing device comprising, separate fuel and lubricant supply chambersadapted to be pressurized by pressure from said crankcase, a mixingchamber, a tube for each of said fuel and lubricant chambers for placingthem in communication with said mixing chamber, the cross sectionalareas of said tubes being of different size and in proportion to theproportion of fuel and lubricant feed desired, and conduit means placingsaid mixing chamber in communication with said carburetor.

3. In combination with an internal combustion engine having apressurized crankcase and also having a carburetor through which a fueland lubricant mixture is passed to said engine, a fuel and lubricantmixing device comprising, separate fuel and lubricant supply chambers, apressure passageway for each of said chambers and in communication withsaid crankcase whereby said chambers are adapted to be pressurized bypressure from said crankcase, said pressure passageway for saidlubricant chamber being of larger cross section than said fuel chamberpassageway whereby pressure build-up is more rapid in said lubricantchamber, a mixing chamber, a tube for each of said fuel and lubricantchambers for placing them in communication with said mixing chamber, andconduit means placing said mixing chamber in communication with saidcarburetor.

4. In combination with a two-stroke internal combustion engine having apressurized crankcase and also having a carburetor through which a fueland lubricant mixture is passed to said engine, a fuel and lubricantmixing device comprising, separate fuel and lubricant supply chambers, apressure passageway for each of said chambers and in communication withsaid crankcase whereby said chambers are adapted to be pressurized bypressure from said crankcase, said pressure passageway for saidlubricant chamber being of larger cross section than said fuel chamberpassageway whereby pressure build-up is more rapid in said lubricantchamber, a mixing chamber,

a tube for each of said fuel and lubricant chambers for placing them incommunication with said mixing chamber, the cross sectional areas ofsaid tubes being of dilferent size and in proportion to the proportionof fuel and lubricant feed desired, and conduit means placing saidmixing chamber in communication with said carburetor.

5. In combination with an internal combustion engine having apressurized crankcase and also having a carburetor through which a fueland lubricant mixture is passed to said engine, a fuel and lubricantmixing device comprising, separate fuel and lubricant supply chambers, apressure conduit placing said crankcase in communication with saidchambers whereby the latter are adapted to be pressurized by pressurefrom said crankcase, said fuel supply chamber being vented to atmosphereto insure continual pressure discharge through said conduit, a mixingchamber, a tube for each of said fuel and lubricant chambers for placingthem in communication with said mixing chamber, and conduit meansplacing said mixing chamber in communication with said carburetor.

6. In combination with an internal combustion engine ,having apressurized crankcase and also having a carburetor through which a fueland lubricant mixture is passed to said engine, a fuel and lubricantmixing device comprising, separate fuel and lubricant supply chambers, apressure conduit placing said crankcase in communication with saidchambers whereby the latter are adapted to be pressurized by pressurefrom said crankcase, said fuel supply chamber being vented to atmosphereto insure continual pressure discharge through said conduit, a mixingchamber, a tube for each of said fuel and lubricant chambers for placingthem in communication with said mixing chamber, conduit means placingsaid mixing chamber in communication with said carburetor, and apressure regulator in said pressure conduit for maintainingsubstantially constant pressure in said fuel and lubricant chambers andpreventing flooding of said carburetor.

7. In combination with an internal combustion engine having apressurized crankcase and also having a carburetor through which a fueland lubricant mixture is passed to'said engine, a fuel and lubricantmixing device comprising, separate fuel and lubricant supply chambers, apressure passageway for said fuel chamber and a smaller pressurepassageway for said lubricant chamber, a pressure conduit connectingsaid passageway to said crankcase whereby pressure in said lubricantchamber builds up faster than in said fuel chamber, a mixing chamber, atube for each of said fuel and lubricant chambers for placing them incommunication with said mixing chamber, the cross sectional area of saidlubricant chamber tube being less than that of said fuel chamber tubewhereby more fuel than lubricant is delivered to said mixing chamber,means placing said mixing chamber in communication with said carburetor,and a pressure regulator in said pressure conduit for minimizingpressure fluctuations in said chambers and thereby preventing floodingof said carburetor.

8. A fuel and lubricant mixing device for an internal combustion enginehaving a pressurized crankcase, said device comprising, separate fueland lubricant supply chambers adapted to be pressurized by pressure fromsaid crankcase, a mixing chamber, a tube for each of said fuel andlubricant chambers for placing them in communication with said mixingchamber, and conduit means chambers adapted to be pressurized bypressure from said crankcase, a mixing chamber, a tube for each of saidfuel and lubricant chambers for placing them in communication with saidmixing chamber, the cross sectional size of said tubes beingproportional to one another in proportion to the feed of fuel andlubricant desired, and conduit means adapted to place said mixingchamber in communication with said engine.

10. A fuel and lubricant mixing device for an internal combustion enginehaving a pressurized crankcase, said device comprising, separate fueland lubricant supply chambers, a pressure passageway for each of saidchambers and adapted to be in communication with said crankcase wherebysaid chambers are adapted to be pressurized by pressure from saidcrankcase, said lubricant chamber passageway being of larger capacitythan said fuel chamber passageway, a mixing chamber, a tube for each ofsaid fuel and lubricant chambers for placing them in communication withsaid mixing chamber, and conduit means adapted to place said mixingchamber in communication with said engine.

11. In combination with an internal combustion engine having apressurized crankcase and also having a carburetor through which a fueland lubricant mixture is passed to said engine, a fuel and lubricantmixing device comprising, separate fuel and lubricant supply chambers, apressure conduit placing said crankcase in communication with Saidchambers whereby the latter are adapted 116 be pressurized by pressurefrom said crankcase, said fuel Supply chamber having a pressure reliefvalve for relieving pressure above a predetermined amount from said fueland lubricant supply chambers, said valve being set to open at apressure below that in said crankcase to there by insure continualpassage of air from the crankcase to said device, a mixing chamber, atube for each of said fuel and lubricant chambers for placing them incommunication with said mixing chambers, and conduit means placing saidmixing chamber in communication with said carburetor.

12. In combination with an internal combustion engine having apressurized crankcase and also having a carburetor through which a fueland lubricant mixture is passed to said engine, a fuel and lubricantmixing device comprising, separate fuel and lubricant supply chambers, apressure conduit placing said crankcase in communication with saidchambers whereby the latter are adapted to be pressurized by pressurefrom'said crankcase, a one-Way check valve in said pressure conduit,said fuel supply chamber having a pressure relief valve for relievingpres- 8 sure above a predetermined amount from said fuel and lubricantsupply c-hambers, said valve being set to open at a pressure below thatin said crankcase to thereby insure continual passage of air from thecrankcase to said device, a mixing chamber, a tube for each of said fueland lubricant chambers for placing them in communication with saidmixing chambers, and conduit means placing said mixing chamber incommunication with said carburetor.

References Cited in the file of this patent UNITED STATES PATENTS1,907,725 Bracke -a May 9, 1933 2,213,418 Swanson Sept. 3, 19402,273,202 Jackson a;. Feb. 17, 1942 2,356,327 Lebus Aug. 22, 19442,603,379 Friend July 15, 1952 FOREIGN PATENTS 678,269 Germany July 12,1939 830,439 Germany -2 Feb. 4, 1952 503,450 Italy Dec. 6, 1954

